Method and tumbler gage for measuring key cuts

ABSTRACT

Key cuts are measured by inserting a key into a holder having tumblers provided with predetermined gage markings, said tumblers being adapted to move a distance corresponding to the depth of the key cut. The tumblers are on both sides of the holders and permit measuring the key cuts on both sides of the key simultaneously.

United States Patent [1 1 Marmel Dec. 4, 1973 [54] METHOD AND TUMBLER GAGE FOR 2,070,228 2/1937 Fitzgerald 33/174 F MEASURING KEY CUTS 3,535,794 lO/l970 Singer 33/174 F [76] Inventor: Noah S. Marmel, I889 Alpha Rd., Primary Examiner Robert Hun Glendale Cahf' 90009 Assistant ExaminerRichard R. Steams 22 Filed; Jam 2 1972 AttorneyRoman A. Dimeo [21] Appi. No.: 221,507 57 ABSTRACT Key cuts are measured by inserting a key into a holder [52] US. Cl. 33/ 174 F having tumblers provided with predetermined gage [51] Int. Cl. GOlb 5/20 markings, said tumblers being adapted to move a dis- [58] Field of Search 33/174 F tance corresponding to the depth of the key cut. The tumblers are on both sides of the holders and permit [56] References Cited measuring the key cuts on both sides of the key simul- UNITED STATES PATENTS taneously- 1,207,217 12/1916 Ross 33/174 F 2 Claims, 4 Drawing Figures IATENTED DEC 4 I975 m Ma EM R mA M S H m v V. B

=4 TTORNEY 1 METHOD AND TUM-BLER GAGE roR MEASURING KEY CUTS BACKGROUND OF THE INVENTION 1. Field of the Invention Method and device for duplicating a key by measuring key cuts, and particularly a device for obtaining the depth of the key cuts so that a duplicate key can be made.

2. Description of the Prior Art A lock has tumblers which, when properly aligned by the key, allow thekey'to move the latch from its closed position. Once a particular key'is cut to fit a lock, no record is made or kept of the key cuts. Thus, when a duplicate key is required, it is often difficult or impossible to obtain one.

This invention overcomes this difficulty by providing a method and meansof determining the key cuts of a key in order to duplicate the same.

SUMMARY OF THEINVENTION A method of measuring key cuts is claimed, in which a key is inserted into a gage havingtumblers that respond to the depth of the key cuts. The tumblers have marks which correspondto-the depth of the key cut. The tumbler marks are read to obtain the depth of key cuts.

A gage'for measuring key cuts comprises a holder adapted to receive a'key, and at least one tumbler having marks correspondingto the depth of the key cuts. The tumbler is adapted to fit the holder and is adapted to move in response to the depth of the key cuts when the key is inserted into the holder.

The holder further comprises a body adapted to hold at least one tumbler and a removable insert adapted to fit within the body. The insert is adapted to align the groove of the key within the body which causes the key cuts to align with the tumbler whenthe' key is inserted.

The body is hollow and'has a central axis, and two ends, one end is closed and the other end is open. The body has a plurality'of bores predeterminedly aligned and spaced perpendicular to and along one side of the central axis. There are a plurality of' tumblers each adapted to moveably fit within the'bores. The tumblers have marks corresponding to thekey cuts. The removeable insert has first and second members. The first member is adapted to fit the open end of the body. The first member has an opening through whicha'key is inserted, the opening'having 'a width andheight corresponding to the particular key being measured, so that it is firmly held during the measurement. The second member has an elongated shape and is adapted to fit the groove of the key and align the key with the tumblers.

The bores of the body'are adapted to receive the tumblers which have marking indicia thereon ina predetermined manner and which extend "laterally into said body so that the inward ends of the tumblers impinge against 'thebase ofthe key cut. Although not mandatory, it is preferablethat the inward ends of the tumblers are tapered'so that the apex of the taper engages the bore of the key cut 'anddisclose a more accurate reading.

The holder can have bores and tumblers on both sides diametrically opposite to each other and perpendicular to the central axis, so that keys with key cuts on both sides can be measured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational sectional view of a key inserted into the gage of the instant invention.

FIG. 2 is an end view of the gage of the instant invention shown in FIG. 1.

FIG. 3 is a side perspective view of a removeable insert.

FIG. 4 is a side elevational view of the removeable insert of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of measuring'the depth of the key cuts of a key comprises inserting a key 10 in a gage 11, such as shown in FIG. 1, having tumblers 12 with visible markings thereon which correspond to the depth of the key cut 16 of key 10. After inserting the key 10 into the gage ll,'the tumbler marks 12c on tumblers 12 are then read to obtain the depth of the key cuts 16.

Gage 11 for measuring the depth of the key cuts 16 comprises a body 13 adapted to receive the key 10 and at least one tumbler 12 which has marks that correspond to the depth of the key cuts 16. The tumbler 12 is adapted to fit the body 13 and is adapted to move in response to the depth of the key-cuts 16 when the key 10 is inserted into the body 13.

In this embodiment of the invention, the gage 11 has a body 13 which is adapted to hold a plurality of tumblers 12. There is also included a removeable key insert 14 (shown in FIG. 2) which fits into the body 13, as

shown in FIG. 1. This removeable insert 14 aligns the key 10 within the body 13 with the tumblers 12, by aligning the groove 10b of the key 10 within the body 13 thereby causing the key cuts 16 to align with the tumblers 12.

In this embodiment of the invention the body 13 is hollow with a central axis which runs from one end at the point where the key 10 is inserted to the center of the opposite end of the body. One end of the body 13 is open while the opposite end thereof may be open or closed. In FIG. 1, body 13 has a cylindrical shape with an open end and a closed end. The central axis runs from the mid-point of the open end through the center of the cylindrical body to the mid-point of the opposite end. The key 10 when inserted lies along this central axis.

The body 13 has at least one, but preferably a plurality of bores 15 which are predeterminately aligned and spaced perpendicular to and along one side of the central axis of body 13. In FIG. 1, the embodiment shown has a plurality of bores 15 on each side of the body 13. The bores 15 as shown, are predeterminately spaced and aligned perpendicular to the central axis and diametrically opposite to each other.

There are a plurality of tumblers 12 each adapted to moveably fit the bores 15. In this embodiment the bores 15 have a cylindrical shape and the tumblers 12 have a cylindrical shape adapted to fit the shape of the bores, but it is understood that the tumblers may be of any cross-sectional configuration including square, triangular and the like, without deviating from the scope of the invention herein. The inward end 12a of each tumbler 12 extends toward the central axis of the cylindrical body 13 and is adapted to impinge against the base or root of the key cuts16. As hereinabove mentioned, it is preferable to provide end 12a with a tapered portion 12b to insure that the tumbler more accurately reads the depth of the key cut. Such tapered portion may be pyramidal or conical as shown herein. In FIG. 1, the tumblers 12 have the apexes of the conical ends 12a impinging against the base of the key cut 16. The apexes of conical ends 12a ride the key cuts 16 when the key is inserted and rests on the base of the key cuts properly show the depth of the key cuts. Each tumbler 12 is provided with visible measuring indicia 120 as shown in FIG. 1 at predetermined positions, and has code values, such as the numbers from one to five assigned to each of the lines so as to coincide with the depth of the key cuts. When the key 10 is inserted, each tumbler 12 moves within its bore 15 a distance corresponding to the depth of the key cut 16 it measures so that only those lines which correspond to the depth of the key cut are visible, and the highest value showing corresponds to the depth of the key cut.

The movement of the tumblers 12 can be controlled by spring means or the like (not shown) to cause the tumblers to positively engage the key cut. In addition retention means may be utilized either with or without said spring means to avoid absolute displacement of the tumblers from the bores of the body. As shown, the retention comprises an aperture 12d in each of tumblers 12 through which retaining pin 12e passes. Retaining pin 12e is anchored in the body 13.

In the embodiment shown in FIG. 1, the removeable key insert 14 fits within the open end 17 of the cylindrical body 13. The removeable insert 14 has a first member 18 which is cylindrical in shape, analogous to a plug which fits within the open end 17 of the body 13. There is an opening 19 provided in the first member 18 having a width and height corresponding to the neck 10a of the particular key being measured, so that the key 10 is firmly held within the gage 11 during the measurement of the key cut depths. The removeable insert 14 has a second member 20, which has an elongated shape adapted to fit the groove 10b of the key being measured. This second member 10b is connected to opening 19 of the first member 18 at a distance predetermined by the type of key being measured, and is in alignment with the tumblers of the gage. When the particular key 10 is inserted, the opening 19 in the removeable insert 14 firmly holds the neck 10a of the key 10 and the elongated member 20 guides the key 10 into the gage l1 and aligns the key cuts 16 with the tumblers 12. A removeable insert is'made to correspond to the particular type of key, for example, a Volkswagen, Ford, Chevrolet, etc. which have their grooves located in different positions and which have different corresponding locks. The elongated member 20 as shown has a rectangular shape adapted to fit the groove 10b of the key 10.

The embodiment shown in FIG. 1 can be used to simultaneously measure keys having key cuts on both sides, or on only one side. If desired, the gage of the instant invention can be constructed so as to have tumblers on only one side, thereby solely measuring the key cuts on the one side. In this latter case, keys with key cuts on both sides would require two measurements. One side would be measured, first, the key would then be removed and reversed and the second side of the key would be measured. For some keys this may require using a different insert to properly align the key cuts with the tumblers.

The invention set forth by the claims is not to be limited by the embodiments described herein. For example, the body could be rectangular in shape and the tumblers could be rectangular. These and other equivalent parts can be substituted without departing from the scope of the invention as set forth in the claims.

I claim:

1. A gage for measuring the depth of key cuts of a key which comprises:

an elongated hollow body, having at least one end thereof open, said body having a plurality of bores laterally passing therethrough so as to intersect the hollow interior of said body;

means in said body for inserting a key therein, said means comprising a removable insert which is accommodated in an open end of said body, said insert having an elongated member extending axially into the hollow interior of said body so as to engage the groove of a key and align the key within the body thereby causing the key cuts of the key to align with said bores in the body when a key is inserted therein;

at least one elongated tumbler having marks correlating to the depth of the key cuts thereon positioned within said bores and in slideable relationship therewith, said tumblers adapted to engage the base of the key cuts when a key is inserted into the body thereby permitting a visual observation of the depth of said key cut; and

means for retaining said tumblers in engagement with said bores.

2. A gage as in claim 1, wherein the key insert has an opening, the height and width of which corresponds to the particular key being measured, so that the key is firmly held within the holder during measurement of the key cuts. 

1. A gage for measuring the depth of key cuts of a key which comprises: an elongated hollow body, having at least one end thereof open, said body having a plurality of bores laterally passing therethrough so as to intersect the hollow interior of said body; means in said body for inserting a key therein, said means comprising a removable insert which is accommodated in an open end of said body, said insert having an elongated member extending axially into the hollow interior of said body so as to engage the groove of a key and align the key within the body thereby causing the key cuts of the key to align with said bores in the body when a key is inserted therein; at least one elongated tumbler having marks correlating to the depth of the key cuts thereon positioned within said bores and in slideable relationship therewith, said tumblers adapted to engage the base of the key cuts when a key is inserted into the body thereby permitting a visual observation of the depth of said key cut; and means for retaining said tumblers in engagement wIth said bores.
 2. A gage as in claim 1, wherein the key insert has an opening, the height and width of which corresponds to the particular key being measured, so that the key is firmly held within the holder during measurement of the key cuts. 